The present invention relates to tarping systems for open-topped containers, such as trailers on hauling vehicles. The invention pertains to improvements in roll tarp systems, and more particularly to end caps for use with such systems.
Various types of truck, trailers and container bodies are designed to be loaded and unloaded through an open top. A typical application of such containers is to haul grain, earth or refuse. It is obviously desirable to provide the container with a covering, such as a flexible tarpaulin, to close the open top and prevent discharge of the materials housed therein during transit. The tarpaulins, or tarps, also serve to shelter the container contents from the elements, such as wind and rain.
Several systems have been developed for covering open-topped containers. Most frequently, these systems involve a flexible tarp unrolled from a tube that spans a length or width dimension of the container. These systems also frequently use curved bows spanning a dimension of the container to provide support for the flexible tarp when it has been unfurled over the loaded container.
Two such tarping systems are the SIDEWINDER™ Tarp System and the KWIK-LOCK™ Roll Tarp manufactured and sold by Aero Industries, Inc. Both systems are adapted for use on long trailers. For the purposes of illustration, reference is made to FIGS. 1 and 2 in which general features of these tarping systems are depicted. Further details of these tarping systems can be found in U.S. Pat. No. 5,002,328 to Michel, and Re. 31,746 to Dimmer et al., the disclosures of which are incorporated herein by reference. As shown in FIG. 1, a roll tarp assembly 10 is mounted on a trailer 12. The assembly includes a flexible cover or tarpaulin 16 that is sized to cover the trailer opening 14 when it is unrolled.
The tarp 16 is rolled onto one side wall 18 of the trailer 12 and supported by a retainer assembly 20. Details of this retainer assembly can be found in the above-mentioned patent to Dimmer et al. The tarp 16 is wound onto a roll tube 22. Like the tarp 16, the roll tube 22 has a length sized to span the length of the trailer 12. Preferably, the roll tube 22 is a rigid metal tube, usually made of aluminum.
The roll tube 22 is rotated by way of a hand crank 25 that drives a crank shaft 26. Rotation of the shaft 26 leads to rotation of the roll tube 22 through a universal joint 27. A crank retainer assembly 28 can be provided to store the crank when not in use. Again, this crank mechanism can be of conventional design, such as the mechanism disclosed in the Dimmer '746 reissue patent.
In the tarping system 10 illustrated in FIGS. 1 and 2, the tarp is unrolled from its rolled configuration 16′ to its extended position 16 over the container opening 14. Tarp bows 32 help support the weight of the tarp when it is drawn across the width of the trailer from side wall to side wall 18. The free end of the tarp can be held in place by a latch plate 30. The details of this latch plate can again be found in the Dimmer '746 Patent, which disclosure is incorporated herein by reference. However, it is understood that other tarp retaining devices can be utilized.
In prior tarping systems, a pair of end cap plates 35 are provided at opposite ends of the container or trailer 12. These end cap plates help support the roll tube 22 and tarp as it is rolled and unrolled. In addition, the plates 35 provide a sealing surface as the tarp 16 is drawn and tightened across the plates 35 in its unrolled configuration. Tension in the tarp 16 pull the tarp edges onto the plates 35 to help prevent flapping during transit and to help protect the trailer contents from the elements. A wind deflector 36 can be provided at the front end of the trailer to provide further isolation of the tarp from the elements.
One detriment with the end cap plates of these prior tarping systems is that transported material has a tendency to collect under the plates. Other end caps have been provided that are somewhat more contoured fore and aft. These contoured end caps can be even more problematic since they encompass a large volume and therefore provide more space for material to collect. The material, such as grain or refuse, amassed beneath the end cap eventually degrades and can foul the end cap and even cause it to corrode. Of course, damage to the end cap compromises its ability to support the tarp and maintain a tight seal against the elements. Eventually, the end cap plate or end cap must be replaced.